Spitzer Space Telescope - Archive Research Proposal #30347


9-D Bayesian Quasar Classification in the Mid-IR/Optical

Principal Investigator: Gordon Richards
           Institution: Johns Hopkins University

Co-Investigators: 
Robert Brunner, University of Illinois                                
Alex Gray, Georgia Tech                                               
Robert Nichol, Portsmouth                                             
Alex Szalay, Johns Hopkins University                                 

Science Category: AGN/quasars/radio galaxies 
Dollars Approved: 49297.0 

Abstract:
One of the hottest topics in extragalactic astronomy is the
identification and census of type 2 quasars.  Type 2 selection
benefits enormously from the high quality imaging data afforded by the
Spitzer Space Telescope since these objects are generally too obscured
in the optical for efficient selection in that bandpass.  We propose
to develop a novel classification algorithm to aid in this endeavor.
Bayesian quasar classification based on Kernel Density Estimation
(Richards et al.  2004) and photometric redshift estimation (Weinstein
et al.  2004) has already been shown to be very efficient in the
optical using only the 5 SDSS bandpasses.  Additional bandpasses, such
as afforded by Spitzer-IRAC imaging, can be used to further improve
this selection method and photometric redshift estimation.  With
appropriate tuning of our algorithms, we can meet two key goals.
First is to construct a catalog of type 1 quasars in the roughly 50
square degrees of sky that currently have (or will have by the end of
2006), public data from both SDSS and Spitzer-IRAC.  Such a catalog
(including accurate photometric redshifts) will enable a second goal,
namely more efficient type 2 quasar searches.  We will improve the
efficiency of type 2 quasar discovery by removing those mid-IR
luminous type 1 quasars from the sample of objects that are currently
being followed-up with multi-object spectroscopy on larger telescopes,
and also by better isolating the type 2 quasar parameter space.  We
request $49927 of support to adapt our classification and photometric
redshift algorithms to make use of the Spitzer-IRAC data and to
publish a catalog of quasars identified by these algorithms.